This invention relates to a resealable easy open closure or end for containers such as cans, jars, bottles and the like.
Easy open ends ("EOE") are can ends (tops) which have a score line or similar weakening segment which weakens the end against a tearing type force but maintain a strength against a vacuum and/or a pressure type force. A pull tab is part of the end and by pulling on the tab the segment of the end which is inside the score line tears off, thus opening the can without the use of a can opener.
In the case of an adhesively sealed EOE, the entire EOE is removed. In the case of drinks (soft drinks, beer, non-carbonated drinks, juices and similar products) only a small section of the end is torn off (or sometimes pushed in and left on inside the can or lifted and left on the outside of the can).
In the case of soups, meats, etc., most of the end is torn off leaving a small segment which is outside the score line (i.e. towards the can wall). If heat or adhesively sealed, no score line is necessary and the entire segment is removed, although a heat or adhesive seal with a score line can also be used.
In the case of an easy open end that is used for sterilized foods such as meat, fish, soups, vegetables, fruits, etc., the part that is torn off is at present usually discarded and no provision for a reseal is generally made--the cans generally being of such size that they are single-use cans or, if multi-use cans, the contents are either transferred to a different closeable container (such as a freezer or refrigerator sealable container) or the top of the opened can is wrapped with foil or plastic.
In those cases not requiring sterilization of the contents, such as dry foods, nuts coffee, candy, crisps (potato or other chips), pretzels and other snack foods, and in the case of bird seed or even sporting goods (e.g. tennis balls) and industrial products (e.g. chemicals or small parts), if an easy open end (which in these cases can also be a membrane (scored or unscored) glued or heat sealed to the container) is provided, a separate plastic snap-on cover is usually also provided. the container itself can be metal, plastic or composite (paper-foil-plastic). Generally, membranes are not used where the products are under substantial pressure or vacuum.
In the case of easy open ends for beverages (soft drinks, beer and non-carbonated beverages), which ends have a small section which is scored or attached with adhesive, the loss of carbonation and/or the sanitary requirements make it difficult to store these products even for a short time, and therefore a screw or bayonet type resealable cap is provided, and this requires two hands to reseal.
Since a resealable easy open end is very useful and desirable, the prior art shows many patents dealing with resealable easy open ends. These patents have common factors, namely, that there is a frame member attached to the can and to which the resealable easy open end is attached. Additionally, these patents may or may not have a tear strip which is attached to the frame member, and may or may not have a part of the end remaining on the can. In all of these cases, there is a plurality of pieces which have to be used to achieve the required function. This group includes U.S. Pat. Nos. 5,758,793, 5,617,968, 5,511,679, 5,125,528, 5,085,339, 5,050,763, 5,042,680, 5,020,686, 4,724,979, 4,724,978, 4,699,290, 4,682,706, 4,660,735, 4,529,100 and 3,557,998.
The partly open end makes it difficult to remove the contents, and the plastic ring to which the end is sealed makes it much more expensive, i.e., two parts instead of one part. The end is also awkward to reseal since two hands have to be used, one to force it over the button and the other to hold the can against this force.
These ends are expensive since either a frame member has to be molded in addition to the removable section or a separate closing cap has to be provided. In addition to the cost which can represent a factor of as much as 20%-80% if not more of the cost of the can, these ends are environmentally unfriendly because either a plastic throw away overcap or an injection molded frame member are needed.
In some cases a hinged flap is also required and part of the lid stays on the can even if it is not a separate member, or a tear strip is required. This group includes U.S. Pat. Nos. 5,145,085, 5,085,339, 5,050,763, 4,741,450, 4,724,979, 4,724,978, 4,699,290, 4,473,168, 4,434,907, 4,433,793, 4,427,128, 4,385,708, 4,165,016, 3,998,354, 3,557,998, 3,356,250 and 2,998,158.
In all of the above patents there is at least one or a combination of a separate frame member that stays on the can, a hinged cover, a part of the cover that stays on the can, a tear strip, a weakening member combined with one of the above, a plurality of pieces, pieces that have to be injection molded (i.e. they cannot be cut from a sheet), weakened members, separate membranes (i.e. two-part ends), or they require double seaming. None of the above patents show a simple, one piece, easily manufactured resealable easy open end.